Hydroxyethyl starches (HESs) are polydisperse, artificial colloids for intravascular volume replacement that are usually derived from the cornstarch amylopectin. HES and HES solutions are highly effective plasma expanders that are particularly useful for the treatment and/or prevention of hypovolemia, acute normovolemic hemodilution, disturbances in capillary blood circulation, as may occur with tinnitus, or the treatment of burns.
The use of HES, however, may lead to its accumulation in plasma and various tissues, and it has been hypothesized that such accumulation may cause unfavorable outcomes, particularly in critically ill patients. In addition, HESs are increasingly misused in sports, especially in high performance endurance sports, even though their use has been banned by the International Olympic Committee (IOC). Therefore, methods for the reliable and sensitive detection of HESs in samples, in particular biological samples, are needed.
Present technologies to measure HESs are either inaccurate, inconvenient and time-consuming, or involve the disadvantageous use of radioactive substances. For example, Leuschner et al. (Drugs R&D 4(6):331-338, 2003) describe the use of a 14C-labeled HES for the determination of tissue storage of HES after intravenous administration to rats. While this method can be considered the gold standard in terms of sensitivity and accuracy, it is dependent on radiolabeling. Similarly, methods involving fluorescent labelling with fluorescein isothiocyanate (FITC) are known but likewise disadvantageous. Furthermore, methods involving the inconvenient and time consuming precipitation of HES by acetone, acidic hydrolysis and/or additional derivatization steps are known.
An object of the present invention, therefore, is the provision of an improved method for the detection of starches in a sample that is more reliable, quick and convenient, as well as more accurate and sensitive than the previously known methods and does not rely on the use of radioactive substances or other labeling. More particularly, the object of the present invention is the provision of such an improved method that allows the detection of starches in a biological sample that has been isolated from an organism and is used “as is”, i.e. untreated and in particular without any preceding precipitation steps.